Preheat oven to 375 degrees. Line a baking sheet pan (18" X 13") with parchment paper. Spray paper and sides lightly with a non-stick baking spray.
Place egg whites in a bowl. Mix with a mixer with a whisk attachment over high speed until light and foamy. With mixer running on a medium speed, slowly add 1/2 cup sugar. Return speed to high and continue mixing until stiff peaks are formed. Carefully remove whites from mixing bowl and set aside.
In same mixing bowl, add egg yolks, 1/4 cup of sugar and vanilla. Mix with whisk attachment over high speed until pale yellow (3-4 minutes).
Add 1/2 egg whites to batter. Gently fold in using a spatula. Repeat with remaining egg whites.
Sprinkle 1/2 flour over egg mixture. Fold gently with a spatula until incorporated. Repeat with remaining flour.
Place batter on prepared baking sheet pan. Spread evenly over baking sheet.
Bake for 8-10 minutes until top is very lightly browned.
Have a clean kitchen towel on counter. Sprinkle with powdered sugar.
When cake is removed from oven, gently loosen the sides of the cake from the pan with a knife. Quickly invert the entire baking sheet pan onto the towel. Remove parchment paper. Starting with the short end, carefully roll cake (with towel). Set aside on a cooling rack until completely cooled.